Filtering systems with integral filter back-flushing

ABSTRACT

A filter system includes a distribution valve operable to direct a received fluid stream to first and second outlets during respective first and second cycles. A filtering system filters at least some fluid output from the first outlet of the distribution valve during the first cycle with a first filter while back-flushing a second filter and filters at least some fluid output from the second outlet of the distribution valve during the second cycle with the second filter while back-flushing the first filter.

FIELD OF INVENTION

The present invention relates in general to fluid filtering techniques,and in particular to filtering systems with integral filterback-flushing.

BACKGROUND OF INVENTION

Fluid filtering technologies have been in existence for a very longtime. Nevertheless, even the most sophisticated of these technologiesare still subject to significant problems, including those related tothe clogging and cleaning of the filters themselves. These problems arecompounded when hazardous or toxic materials are involved, which makefilter cleaning a difficult, and often hazardous, task.

Consider for example a system for recovering water from a typical septicsystem used in residences, small business enterprises, and the like. Inthis case, waste water received from a sewer line is first received in atrash tank where solid organic waste materials settle-out. The remainingeffluent is then moved to an aerobic tank, using either pumping orgravity flow, where air is pumped into the effluent to help breakdownthe remaining organic matter. The effluent is then moved, using eitherDumping or gravity flow, to a holding tank, where it is held and thenperiodically pumped out through a filter system to a leaching area. Thisleaching area can be, for example, a small plot of soil suitable forgrowing plants and can be serviced a drip irrigation system or similarmeans of water distribution coupled to the filter system.

As with many types of fluid filtering systems, the filter between theholding tank and the leaching area can become clogged and thereforerequire cleaning. In a septic system, cleaning the filter can not onlybe a difficult task, but also a hazardous one, given the organic natureof the waste being handled.

The need for more efficient fluid filtering systems suitable for a widerange of applications is generally desirable. Filtering techniques,which improve the efficiency and safety of systems handling potentiallyhazardous fluids, such septic system effluent, are particularlydesirable.

SUMMARY OF INVENTION

The principles of the present invention are embodied in filteringsystems that perform automatic back-flushing without human intervention.According to one representative embodiment, a filter system is disclosedthat includes a distribution valve operable to direct a received fluidstream to first and second outlets during respective first and secondcycles. A filtering system filters at least some fluid output from thefirst outlet of the distribution valve during the first cycle with afirst filter while back-flushing a second filter and filters at leastsome fluid output from the second outlet of the distribution valveduring the second cycle with the second filter while back-flushing thefirst filter.

Advantageously, the principles of the present invention provide for thedesign and construction of filtering systems that are subject to minimalclogging and/or that require minimal human intervention to maintain peakperformance. Furthermore, when such filter systems are used in systemstreating potentially hazardous materials, for example the effluent inseptic systems, human exposure to such potentially hazardous materialsis also minimized. Moreover, filter systems according to the inventiveprinciples do not require electricity or a like power source to switchbetween operating cycles.

BRIEF DESCRIPTION OF DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIG. 1A is a block diagram of a typical septic/waste water recoverysystem suitable for describing one application of the principles of thepresent invention;

FIG. 1B is a diagram illustrating another typical septic/waste waterrecovery system suitable for describing the inventive principles;

FIGS. 2A-2C are diagrams respectively showing top, side, and front-endviews of a filtering system embodying the principles of the presentinvention and suitable for use in the systems shown in FIGS. 1A and 1B;

FIGS. 3A and 3B are more detailed diagrams of flush valves shown inFIGS. 2A-2C; and

FIGS. 4A and 4B are conceptual flow charts illustrating the operationsof the filter system shown in FIGS. 2A-2C.

DETAILED DESCRIPTION OF THE INVENTION

The principles of the present invention and their advantages are bestunderstood by referring to the illustrated embodiment depicted in FIGS.1-4 of the drawings, in which like numbers designate like parts.

FIG. 1A is a diagram of an exemplary septic/waste water recovery system100 suitable for describing one particular application of the principlesof the present invention, although these principles can be applied to awide range of other fluid filtering systems.

As shown in FIG. 1A, system 100 includes an effluent input line 101,which receives effluent from the drains of a house or small commercialconcern. This effluent enters a trash tank 102 through trash tank inlet103. Generally, the effluent remains in trash tank 102 while organicsolids settle-out. After settling, the remaining liquid effluent intrash tank 102 is transferred through outlet 104 and inlet 107, usingeither pumping or gravity flow, into aerobic tank 105, where a pump 106pumps air into the effluent to help break down any remaining organicmatter.

Next, the effluent in aerobic tank 105 is transferred using eitherpumping or gravity flow through outlet 108 and an optional chlorinator109 and into holding tank 110. An irrigation pump 111, controlled by afloat 112, pumps fluid from holding tank 110 through a line 113 tofilter system 114. Filter system 114, which embodies the principles ofthe present invention, will be described in further detail below. In thepreferred embodiment, float 112 enables the operation of irrigation pump111 when sufficient fluid resides at the bottom of holding tank 110. Inaddition, irrigation pump 111 includes a timer, such that whenirrigation pump 111 is enabled by float 112, irrigation pump 111periodically pumps fluid through filter system 114 for a predeterminedamount of time.

In system 100, the filtered water pumped through filter system 114passes through a line or pipe 115 to drip irrigation field lines 116(i.e. the disposal field in this example). In the illustratedembodiment, a back-flush valve/vacuum break 117 is provided between line115 and drip irrigation field lines 116. Return water flows through lineor pipe 118 back through filter system 114 and line 119 into holdingtank 110. An additional line, 120, allows water, which is used in thefilter back-flushing operations described below and which potentiallycontains organic contaminates, to be returned to trash tank 102.

FIG. 1B illustrates an alternate embodiment of septic system 100, whichuses an alternate configuration of filter system 114. The twoembodiments of system 100 shown in FIGS. 1A and 1B operate essentiallythe same way.

A preferred embodiment of Filter 114 shown in FIGS. 1A and 1B is shownin particular detail in FIGS. 2A-2C. Generally, filter system 114includes at least two filtering subsystems, which provide fluid to thedisposal area on alternate pump cycles. During at least a portion ofeach pump cycle, the filtering subsystem which is not being used toprovide fluid to the disposal area is back-flushed to prevent clogging.

The embodiment of filter system 114 shown in FIGS. 2A-2C is based uponan automatic distribution valve 201. Automatic distribution value 201 ispreferably a commercially available product, such at those availablefrom K-Rain of West Palm Beach, Fla.

Automatic distribution valve 201 includes Ports A and B, which arealternately coupled to the associated fluid pump (not shown). Inparticular, Port A is coupled to a first filtering subsystem, theprimary components of which are a standard effluent filter 202 a, acheck valve 203 a, a flush valve 204 a, and a check valve 205 a. Asecond filter subsystem, coupled to Port B of automatic distributionvalve 201, includes an effluent filter 202 b, a check valve 203 b, aflush valve 204 b, and a check valve 205 b. Advantageously, automaticdistribution valve automatically 201 switches between Port A and Ports Bon alternating pump cycles without the use of any electrical switchingcomponents. (It should be recognized that in alternate embodiments,automatic distribution valve 201 may have more than two (2) portsoperating in multiple pump cycles to support a corresponding number offilter subsystems.)

Each subsystem A and B includes interconnection components includingsections of pipe or tube 206, elbows 207, 21 1, and 219, unions 208,flexible sections of tube or pipe 209, T's 210, reducing tees 212,couplings 213, reducing bushing spigots 214, a 90 degree elbow 215, across 216, female adaptors 217, and a reducing elbow spigot 218. In theillustrated embodiment, each of these components is preferably made ofPVC or similar material, although in alternate embodiments othermaterials, such as metal, may be used. System 100 also includes a 0-90PSI pressure gauge 220.

FIG. 3A is a more detailed diagram of a selected one of flush valves 204a and 204 b of FIGS. 2A-2C. FIG. 3B is a partial view taken along Line3B-3B of FIG. 3A.

The embodiment shown in FIG. 3A includes a tee 301 which couples to thecorresponding conduit (pipe or tube) 211 shown in FIG. 2B through abushing 311. One arm of tee 301 couples through a bushing 302 to aconduit (tube or pipe) 308, which is enclosed in a housing including abushing 302, a conduit (pipe or tube) 303, couplings 304, and a bushing306. Two buoyant plastic balls 305 are disposed within conduit 308.

The opposite side of conduit 308 is coupled through a tee 301 and a bulltee 314 to a hose adapter 315. Hose adapter 315 in turn connects througha pressure controlled drain valve 316 and line 119 back to holding tank110 of FIGS. 1A and 1B. Bull tee 314 further couples through a barbedfitting 318 to a tube 319, which in turn connects to cross-feed 228 ofFIG. 2A. In the illustrated embodiment, pressure controlled drain valve316 opens when the pressure applied to bull tee 314 goes below 7 PSI.

Tee 301 further couples through a conduit (tube or pipe) 313, union 309,elbow 310, and bushing 311, to a conduit (pipe or tube) 312. Conduit 312in turn connects through line 120 back to trash tank 102 of FIGS. 1A and1B.

The operation of the preferred embodiment of filter system 114 shown inFIGS. 2A-2C and FIGS. 3A-3B is illustrated in FIGS. 4A and 4B, whichgenerally depict fluid flow for two alternating pump cycles. Inparticular, FIG. 4A shows a typical cycle (Pump Cycle 1) in which fluidis being output from Port A of automatic distribution valve 201,subsystem A is providing fluid to the disposal area, and subsystem B isbeing back-flushed. FIG. 4B illustrates a typical cycle (Pump Cycle 2)in which fluid is being output from Port B of automatic distributionvalue 201, subsystem B is providing fluid to the disposal area, andsubsystem A is being back-flushed. In FIGS. 4A and 4B, dashed linesindicate the movement of water, while solid lines indicate thoseportions of the system which are static (i.e. in which no fluid isflowing).

As shown in FIG. 4A, a portion of the fluid output from Port A ofautomatic distribution valve 201 flows through check valve 203 a andthrough filter 202 a in the forward direction. A portion of the fluidtraveling through filter 202 a goes on to the to the disposal area,while some of this fluid goes through filter 202 b in the reversedirection, thereby back-flushing filter 202 b.

Another portion of the fluid output from Port A of automaticdistribution valve 201 flows through check valve 205 a. This fluid flowcauses buoyant balls 305 of flush valve 204 a to rise and close flushvalve 204 a. At the same time, fluid through open check valve 205 abegins to flow through tube 319 of bull tee 314 of flush valve 204 a andcross-feed conduit 228. (During Pump Cycle 1, since no fluid is flowingthrough Port B of automatic distribution valve 201, check valve 205 b isclosed.)

The fluid flowing through cross-feed conduit 228 begins to force buoyantplastic balls 305 within flush valve 204 b to rise. By controlling thediameter of cross-feed to tube 228, the rate at which buoyant plasticballs 305 rise can be controlled, and hence the time during which flushvalve 204 b remains open.

During the period in which buoyant balls 305 within flush valve 204 bare rising, back-flushing fluid flowing through filter 202 b is allowedto pass through flush valve 204 b and back to trash tank 102 of FIGS. 1Aand 1B. Advantageously, any hazardous contaminates which haveaccumulated within filter 202 b are flushed back into trash tank 102without either leaving the system or coming in to human contact.

Once buoyant plastic balls 305 of flush valve 204 b reach thecorresponding tee 301, flush valve 204 b turns off, and back-flushing offilter 202 b stops. Fluid continues to be pumped through filter 202 aand on to the disposal area during Pump Cycle 1.

At the end of Pump Cycle 1, fluid flow through open check valve 205 astops, and hence no pressure is applied to pressure controlled drainvalve 316 of flush valve 204 a. Additionally, the fluid flow throughcross-feed tube 228 to flush valve 204 b also stops. Consequently,without pressure being applied, pressure controlled drain valves 316 ofboth flush valves 204 a and 204 b open, and the fluid within therespective conduits 308 drains back into holding tank 110. Thecorresponding buoyant plastic balls 305 fall and flush valves 204 a and204 b are ready for Pump Cycle 2.

Pump cycle 2, as shown in FIG. 4B, proceeds similar to Pump Cycle 1shown in FIG. 4A. In this case, filter 202 b is providing fluid to thedisposal area, while filter 202 a is being back-flushed under thecontrol of flush valve 204 a.

In an alternate embodiment, a ball valve or similar valve can bedisposed within the fluid path of cross-feed 228 of FIG. 2A to controlthe back-flushing duration. This optional valve 401 is shown in brokenlines in FIGS. 4A and 4B. In particular, to decrease the rate ofback-flushing, valve 401 is opened to increase the rate of flow into thegiven flush valve 204, with the shortest back-flushing period resultingwhen valve 401 is fully open. On the other hand, to increase the rate ofback-flushing valve 401 is closed to decrease the flow into the givenflush valve 204.

Although the invention has been described with reference to specificembodiments, these descriptions are not meant to be construed in alimiting sense. Various modifications of the disclosed embodiments, aswell as alternative embodiments of the invention, will become apparentto persons skilled in the art upon reference to the description of theinvention. It should be appreciated by those skilled in the art that theconception and the specific embodiment disclosed might be readilyutilized as a basis for modifying or designing other structures forcarrying out the same purposes of the present invention. It should alsobe realized by those skilled in the art that such equivalentconstructions do not depart from the spirit and scope of the inventionas set forth in the appended claims.

It is therefore contemplated that the claims will cover any suchmodifications or embodiments that fall within the true scope of theinvention.

1. A filter system comprising: a distribution valve operable to direct areceived fluid stream to a first outlet during a first cycle and asecond outlet during a second cycle; and a filtering system includingfirst and second filters and operable to: filter at least some fluidoutput from the first outlet of the distribution valve during the firstcycle with the first filter while back-flushing the second filter; andfilter at least some fluid output from the second outlet of thedistribution valve during the second cycle with the second filter whileback-flushing the first filter.
 2. The filter system of claim 1, whereinthe filtering system further comprises: a first valve for coupling fluidfrom the first outlet of the distribution valve through the first filterin a forward direction and through the second filter in a reversedirection; a second valve having a control inlet for receiving fluid forcontrolling the reverse direction fluid flow through the second filterto control back-flushing duration; and a third valve for coupling fluidfrom the first outlet of the distribution valve to the control inlet ofthe second valve.
 3. The filter system of claim 2, wherein the filteringsystem further comprises: a fourth valve for coupling fluid from thesecond outlet of the distribution valve through the second filter in aforward direction and through the first filter in a reverse direction; afifth valve having a control inlet for receiving fluid for controllingthe reverse direction fluid flow through the first filter to controlback-flushing duration; and a sixth valve for coupling fluid from thesecond outlet of the distribution valve to the control inlet of thefifth valve.
 4. The filter system of claim 2, wherein the second valvecomprises: a conduit having an inlet and an outlet for passing reversedirection fluid flow from the second filter during back-flushing; and afloat mechanism for controlling fluid flow through the conduit outlet inresponse to fluid received at the control inlet from the third valve. 5.The filter system of claim 4, wherein float mechanism comprises: asecond conduit having an upper outlet in fluid communication with theconduit; a least one buoyant member disposed within the second conduit;and wherein the control inlet is in fluid communication with a lowerinlet of the second conduit for forcing the buoyant member to the upperoutlet for restricting fluid flow through the conduit.
 6. The filtersystem of claim 5, further comprising drain valve responsive to a changein fluid pressure received at the control inlet for draining fluid fromthe second conduit.
 7. The filter system of claim 3, wherein the fifthvalve comprises: a conduit having an inlet and an outlet for passingreverse direction fluid flow from the second filter duringback-flushing; and a float mechanism for controlling fluid flow throughthe conduit outlet in response to fluid received at the control inletfrom the third valve.
 8. The filter system of claim 7, wherein floatmechanism comprises: a second conduit having an upper outlet in fluidcommunication with the conduit; a least one buoyant member disposedwithin the second conduit; and wherein the control inlet is in fluidcommunication with a lower inlet of the second conduit for forcing thebuoyant member to the upper outlet for restricting fluid flow throughthe conduit.
 9. The filter system of claim 8, further comprising drainvalve responsive to a change in fluid pressure received at the controlinlet for draining fluid from the second conduit.
 10. A filter systemcomprising: a distribution valve operable to direct a received fluidstream to a first outlet during a first cycle and a second outlet duringa second cycle; a first valve operable during the first cycle to couplefluid from the first outlet of the distribution valve through the firstfilter for output from the system and through the second filter forback-flushing; a second valve for controlling back-flushing durationthrough the second filter during the first cycle; a third valve operableduring the second cycle to couple fluid from the second outlet of thedistribution valve through the second filter for output from the systemand through the first filter for back-flushing; and a fourth valve forcontrolling back-flushing duration through the first filter during thesecond cycle.
 11. The system of claim 10, wherein the second and fourthvalves are responsive to received control fluid and the system furthercomprises: a fifth valve operable during the first cycle to providefluid to the second valve for timing the back-flushing duration and tothe fourth valve for turning-off the fourth valve; and a sixth valveoperable during the second cycle to provide fluid to the fourth valvefor timing the back-flushing duration and to the second valve forturning-off the second valve.
 12. The system of claim 11, wherein thesecond and fourth valves each comprise: a conduit for passingback-flushed fluid from the corresponding one of the first and secondfilters to a discharge outlet; and a float mechanism for controllingfluid flow through the conduit outlet in response to fluid received fromthe corresponding one of the fifth and sixth valves.
 13. The system ofclaim 12, wherein float mechanism comprises: a second conduit having anupper outlet in fluid communication with the conduit; a least onebuoyant member disposed within the second conduit; and wherein thecorresponding one of the fifth and sixth valves is in fluidcommunication with a lower inlet of the second conduit for forcing thebuoyant member to the upper outlet for restricting fluid flow throughthe conduit.
 14. The system of claim 12, wherein the second and fourthvalves further comprise a drain valve responsive to a change in fluidpressure for draining fluid from the second conduit.
 15. A fluidrecovery system comprising: a first tank for storing potentiallyhazardous fluid; a second tank for holding fluid received from the firsttank after treatment; and a filter system for filtering at least somefluid pumped from the second tank with a first filter while concurrentlyback-flushing a second filter with at least some fluid pumped from thesecond tank, wherein the fluid back-flushing the second filter isreturned to the first tank.
 16. The fluid recovery system of claim 15,wherein the filter system is further operable to filter at least somefluid pumped from the second tank with the second filter whileconcurrently back-flushing the first filter with at least some fluidpumped from the second tank, wherein the fluid back-flushing the firstfilter is returned to the first tank.
 17. The fluid recovery system ofclaim 16, wherein the filter system comprises: a distribution valveoperable to direct a fluid stream pumped from the second tank to anoutlet during an operating cycle; and a valve system operable during theoperating cycle to direct at least some fluid from the outlet of thedistribution valve through the first filter in a forward direction andthrough the second filter in a reverse direction.
 18. The fluid recoverysystem of claim 17, wherein: the distribution valve is operable todirect a fluid stream pumped from the second tank to another outletduring another operating cycle; and the valve system is operable duringthe another operating cycle to direct at least some fluid from theanother outlet of the distribution valve through the second filter in aforward direction and through the first filter in a reverse direction.19. The fluid recovery system of claim 15, wherein the first tank storesorganic waste.
 20. The fluid recovery system of claim 15, wherein thefirst and second tanks comprise a portion of a septic system.